Protective sheath for a fiberoptic image guide within an articulated endoscope

Abstract

An improved endoscope prevents abrasion of a fiberoptic image guide with a braid reinforced sheath. Abrasion of fiberoptic image guides within articulating endoscopes quickly wear through a conventional fiberoptic mantle, decreasing the useful life of the endoscope. Preferably, the sheath comprises a metal braid disposed within a polyimide, which effectively protects the image guide from abrasion against the endoscope components and substantially extends useful life.

What is claimed is: 
     
       1. An improved endoscope of the type having an articulating tip including an outer tube containing a pulling wire and a fiberoptic image guide, wherein the pulling wire is affixed to the distal end of the outer tube so that a proximal displacement of the pulling wire relative to the outer tube flexes the articulating tip, the improvement comprising: an inner sheath disposed over the image guide within the outer tube of the articulating tip, at least an axial portion of the inner sheath and image guide being radially unrestrained within the outer tube, the inner sheath comprising a polymer material and a reinforcing braid to protect the image guide from abrasion, the reinforcing braid comprising a metal or high strength fiber.   
     
     
       2. An improved endoscope as claimed in claim 1, wherein the reinforcing braid is disposed within the polymer material. 
     
     
       3. An improved endoscope as claimed in claim 2, wherein the polymer material is coextruded with the reinforcing braid. 
     
     
       4. An improved endoscope as claimed in claim 1, wherein the polymer material comprises a polyamide or a high strength thermoplastic elastomer. 
     
     
       5. An improved endoscope as claimed in claim 1, wherein the inner sheath is formed by dip-coating an inner polymer layer and braid with an outer polymer layer. 
     
     
       6. An improved endoscope as claimed in claim 1, wherein the reinforcing braid comprises a metal. 
     
     
       7. An improved endoscope as claimed in claim 1, wherein the outer tube defines a lumen having an axis, and wherein the image guide and the inner sheath within the articulating tip are axially flexible so as to deflect laterally within the lumen of the outer tube to allow the articulating tip to flex when the pulling wire is displaced proximally. 
     
     
       8. An endoscope comprising: an articulating tip having a proximal end and a distal end, the articulating tip comprising an outer tube defining a lumen, the outer tube including a plurality of metallic rings and an elastomeric material;   a pulling wire disposed within the articulating tip and affixed to the distal end;   a fiberoptic image guide disposed within the lumen of the articulating tip and having a distal lens affixed to the distal end, at least an axial portion of the image guide radially unrestrained within the lumen; and   an inner sheath disposed over the image guide within the lumen of the articulating tip, the inner sheath comprising a metallic reinforcing braid disposed within a polymer;   wherein proximally displacing the pulling wire relative to the proximal end of the articulating tip flexes the articulating tip and reorients the lens, the inner sheath deflecting laterally within the lumen with the image guide during flexing of the articulating tip so that the inner sheath prevents contact damage to the image guide from contacting against at least the outer tube and the pulling wire.   
     
     
       9. An endoscope as claimed in claim 8, wherein the outer tube defines an axis, and wherein the image guide and the inner sheath within the articulating tip are axially flexible to allow the articulating tip to flex when the pulling wire is displaced proximally.